A. A state bank may assume secondary liability as an endorser of a negotiable or nonnegotiable instrument, which it owns or has received for collection. A state bank may assume the liability of the guarantor of the genuineness of a signature.
B. Except as expressly permitted in the Banking Act, a state bank shall not assume liability as an insurer or as a guarantor or indorser [endorser] of any security instrument or obligation.